It's hard not to root for people like Deborah Winshel at BlackRock and others who are championing the notion of making the world a better place through what's known as "impact investing."

Winshel, according to Adam Satariano's excellent profile in the latest Bloomberg Businessweek, "has become one of the world’s most influential impact investors, helping set strategy for $7.5 billion of funds for BlackRock." Her bonafides as a financial-world do-gooder are rock solid, with a previous resume entry as president of the Robin Hood Foundation, which fights poverty and throws one of the most can't-miss investment conferences of the year to boot. "You can't fake this one," one BlackRock executive said about Winshel's motivations.

Still, Wall Street being Wall Street and all, it's also hard not to be skeptical about financial services firms' head-first plunge into impact investing or ESG (short for environmental, social and governance) investing over the last few years.

For one thing, there is the underlying theme that this will be the way to butter up the idealistic millennial generation before they inherit tens of trillions of dollars from baby boomer parents.

From the announcement of the BlackRock Impact U.S. Equity Fund in October:

According to US Trust, 67% of millennials state that their investment decisions express their social, political or environmental values. In addition, Morgan Stanley Institute for Sustainable Investing shows that 76% of female investors believe environmental or social factors are important considerations in making investment decisions.

What then of all us old men? Who knows. Maybe the most important investment consideration for that demographic is making sure they have the best promo code on Fan Duel.

Additionally, even for us old men, it's hard not to be skeptical of how much impact an investor can have using a mutual fund or exchange-traded fund dedicated to impact or ESG investing.

The BlackRock Impact U.S. Equity Fund's top holdings do not look drastically different from those with the heaviest weightings in the S&P 500.

There are some notable differences. The fund avoids certain companies and industries such as alcohol, tobacco and weapons. General Electric and Berkshire Hathaway were among the top 10 weights in the S&P 500 and Russell 3000 Index as of Oct. 30 but are not represented in the fund.

BlackRock's own iShares MSCI USA ESG Select Social Index Fund appears to be more aggressive in screening for conscience-easing stocks. It only shares two of its top 10 holdings with the S&P 500 -- Apple and Microsoft. NextEra Energy and 3M are its biggest holdings, each accounting for more than 4 percent of the $370 million ETF.

Where investors will definitely notice an impact, however, is in how much it costs to get into the new mutual fund. The Impact Fund charges a "front-end load" of 5.25 percent, which means that if investors put $10,000 in the fund, they can kiss $525 goodbye immediately. There are discounts and fee waivers for investors who have a certain amount in BlackRock funds or invest through certain retirement plans. But otherwise, investing in front-load funds is often considered a bad idea considering the plentiful cheaper options.

While once common, front-load funds have dwindled. About 15 percent of U.S. equity funds have a front-end load, according to Morningstar. Investors have been avoiding these types of funds en masse.

The load in this case may not matter if investors are a) impressed with the positive impact the fund will have on the world or b) the fund handily outperforms.

Study after study has indicated that investing with your conscience does not necessarily mean sacrificing returns, and in fact can lead to market-beating returns in some cases. Can BlackRock achieve that with its Impact Fund? That seems like it will be a difficult feat. So it might end up being a high price to pay for a clear conscience.

This column does not necessarily reflect the opinion of Bloomberg LP and its owners.

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